Why the Cube Can not display full?

[zzhgithub]

I'm making a mincraft like game. When i try to use ray-cast to choose voxel.But sometimes it can not display full cube wireframe.
why? I render mesh and disaplay diff texture by using shader wgls. when curos move it move Cube to the position. but Wow Look the Pic.
the whole code is on https://github.com/zzhgithub/just_join/tree/player
the core code for cast-ray is no https://github.com/zzhgithub/just_join/blob/player/src/ray_cast.rs
Please help me ! Thanks.😂 :ferris: